Fire control for stud driver



Oct. 4, 1955 M. H. WALKER FIRE CONTROL FOR STUD DRIVER 3 Sheets-Sheet 1 Filed June 5, 1953 r @U \w NM 5 N mm mm INVENTOR. MERLE H. WALKER ATTORNEYS Oct. 4, 1955 M. H. WALKER FIRE CONTROL FOR STUD DRIVER 3 Sheets-Sheet 2 Filed June 5, 1953 Oct. 4, 1955 M. H. WALKER FIRE CONTROL FOR STUD DRIVER 3 Sheets-Sheet 3 Filed June 5, 1953 r r m u 4/? :3 f/ 7 INVENTOR. M51515 /7. I/I/AL/(f/P ATTORNEYS8 FIRE CONTROL FOR STUD DRIVER Merle H. Walker, Ilion, N. Y., assignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application June 5, 1953, Serial No. 359,794

9 Claims. (Cl. 1106) This invention relates a to fire control device for an explosively actuated stud driver.

Explosively powered stud drivers are commonly employed in the construction trades to drive fasteners into steel and masonry structures. For safety, it has been a common practice to provide arrangements which prevented firing unless the stud driver was firmly pressed against the surface into which a stud was to be driven. These safety devices took various forms, some of them moving a chambered cartridge into position where it could be reached by a firing pin only when work contact was established and others serving to release devices locking the trigger or striker controlling sear only when a safe condition had been established.

It is the object of this invention to provide a fire control device in which the striker is cocked or in a position from which it can deliver a blow to fire a cartridge only when engagement with the work surface has established a safe condition for firing.

It is contemplated that the best method of accomplishing this objective is to provide a work surface engaging member projecting in advance of the stud driver which will contact the work surface before the stud driver reaches a firing position and to provide an intermediate cocking element having releasable pushing engagement between this work surface engaging member and the striker or firing pin so that as the stud driver proper is advanced to firing position, the firing pin is held in a fixed position relative to the work surface and thereby retracted relative to the stud driver and against the urging of a firing pin spring. With the provision of means to release the firing pin from the work surface engaging member only when the stud driver has been advanced to the desired firing position, the arrangement is complete. If, however, it should be decided not to fire and the stud driver should be lifted from the work,

the work surface engaging member will return to its normal position and the firing pin will be returned to its uncocked position.

Most conveniently,the work surface engaging member can include a tubular body slidable on the barrel of the stud driver and projecting in advance of the muzzle thereof by an amount at least equal to the distance that the firing pin must be retracted in cocking. The pushing engagement between the projecting work surface engaging member and the firing pinmay readily be provided by a cocking element carried by firing pin or by a cocking element associated with the work surface engaging member, such elements being respectively releasably engageable with the work surface engaging member and the firing pin. Alternatively, the cocking element may take the form of a separately mounted element releasably engageable with both the work surface engaging member and the firing pin and releasable from one or the other, or both, In either case, a trigger operated disconnector is provided to urge the cocking ele- The exact nature of the invention as well as other objects and advantages thereof will become more apparent by consideration of the following specification referring to the attached drawings in which:

Fig. 1 is a longitudinal sectional view through a stud driver incorporating my improved fire control mechanism.

Fig. 2 is a similar view of the stud driver pressed against the work in firing position.

Fig. 3 is a similar view of the stud driver still pressed against the work but with the firing mechanism in fired position.

Fig. 4 is a partial sectional view corresponding to Fig. 2, showing a modification in the cocking element.

Figs. 5 and 6 are partial sectional views corresponding respectively to Figs. 2 and 3, showing another modification in the cocking element.

Fig. 7 is a. partial sectional view in a plane at substantially a right angle to that shown in Figs. 5 and 6, with the mechanism shown in the same position as in Fig. 6. The plane of this view is indicated at 77 on Fig. 8.

Fig. 8 is a cross-sectional view taken on the plane 8-8 of Fig. 7.

Fig. 9 is an enlarged fragment of Fig. 7.

Fig. 10 is an enlarged view of the cocking element shown in Figs. 5 through 8.

Referring to the drawings by characters of reference, it will be seen that I have shown in Figs. 1, 2 and 3 a stud driving tool conforming in many particulars to that shown in my prior application Serial No. 225,146, filed May 8, 1951, and issued as U. S. Letters Patent No. 2,645,772, on July 21, 1953, entitled Stud Driving Tool. To minimize the need for reference to that application, it may be noted that the present tool has, in common with that of my prior application, a basic structure comprising a barrel 1 threaded into a frame plate 2. This frame plate is secured by a hinge bolt 3 to a breech block 4 which forms a closure for the chambered end of the barrel. To the breech block 4 there is secured a housing 5 which encloses a space bounded on one side by the breech block 4 within which there is mounted the firing mechanism to be later described. The housing may have formed integrally therewith a handle 6.

An action tube 7 and action tube extension 8 are slidably mounted on the barrel 1 and urged toward the muzzle thereof by a spring 9 engaged between a shoulder 10 on the barrel and the end 11 of the action tube extension. An action tube cover 12 secured to the frame plate 2 encloses the breech end of the barrel and the action tube and by engagement with the end 13 of the action tube serves as a stop to limit displacement of the action tube toward the muzzle of the barrel.

The action tube extension may be provided with a conical or other type of safety shield 14 which may include a filler 15 of rubberlike material. This assembly of the action tube, action tube extension, and shield comprises a work surface engaging member and the shield end thereof is adapted to be brought into engagement with the work surface into which a stud is to be driven. When the stud driver is advanced toward the work a sufiicient distance tobring the muzzle of the barrelnearly into contact with the work surface, the action tube extension and action tube remain stationary so that the stud driver is advanced against the thrust of the spring 9.

An action tube finger 16 is secured to the action tube and when the barrel is advanced relative to the action tube, as discussed above, projects through aligned holes 17 and 18, respectively, in the frame plate and breech block into the space enclosed by the breech housing. In my prior tool previously referred to, this operation of the action tube finger released a safety lock controlling the fire control and had the dual function of insuring that the stud driver was properly positioned relative tothe work surface and that the breech of the barrel was properly closed by the breech block before firing could take place.

' These functions are retained in my present design but the operation of the fire control has been considerably changed, as will now be discussed.

In my present design, I have supported a firing pin 19 for axial reciprocating movement and urge it toward the breech end of the barrel by a firing pin spring 20. The tip 21 of the firing pin is adapted to pass through the breech block to actuate a percussion primed cartridge in the usual manner. Primary retraction of this firing pin to avoid interference in opening and closing the breech is provided as in my prior application by utilization of the breech latch 22 which passes transversely across the rear face of the breech block and has a wedgelike engagement beneath the firing pin when. the latch is moved to unlatch the breech block from the frame plate. To insure that the firing pin will have only reciprocating movement, a guide pin 23 is secured in the breech block and operates in a hole 24 in the firing pin body 25.

A cocking element is provided by a transversely movable plunger 26 mounted in the firing pin body 25 and urged outwardly by a spring 27. this outward movement being limited by a crosspin 28 in the firing pin body engaged in a slot 29 in the plunger. This plunger is so located in the firing pin body as to encounter the end of the action tube finger 16 when that finger is caused to project through the aligned holes in frame plate and breech block by the advancement of the stud driver relative thereto. The action tube finger therefore arrests the movement of the firing pin, holding it in a fixed position, as shown in Fig. 2, while the rest of the stud driver is advanced and the spring 20 is compressed. I have, in this way, provided a means of cocking thefiring pin when the stud driver is placed in the desired relation to the work surface, which means will also serve to gradually lower the firing pin relative to the breech block if the stud driver is withdrawn from the work surface without firing.

Still referring particularly to Fig. 2, it will be noted that I have provided a trigger 30 which engages with one arm 31 of a disconnector lever 32. A second arm 33 on the disconnector lever is normally positioned just clear of the position occupied by the end of the plunger 26 when the firing pin is in cocked position.

A cartridge may be fired by pulling the trigger rearwardly, as shown in Fig. 3, which turns the disconnector and urges the plunger back into the firing pin body. As soon as the plunger clears the end of the action tube finger, it is free from restraint by that finger and the cocked spring at once urges the firing pin forwardly to fire the cartridge. Obviously, when the tool is lifted from the work, the action tube finger will tend to remain in contact with the work and as the stud driver is withdrawn the plunger may move outwardly into position over the end of the action tube finger to be re-engaged the next time the tool is advanced toward the work to be fired.

In Fig. 4 I have shown a modification of my device where the cocking element takes the form of a detent 34 mounted in the end of the action tube finger 16 and urged by a spring 35 to swing into position to engage beneath a step 36 on a firing pin body 37. As in the case of the preceding modification, a disconnector 38 is provided and operated by a trigger 39. In this case an arm 49 on the disconnector is positioned to engage the tail 41 of the cocking element when the firing pin is cocked and, on pulling the trigger, the disconnector disengages the cocking element 34 from beneath the step 36 on the firing pin body. The showing in Fig. 4 corresponds to Fig. 2 in that the firingv pin is shown cocked and ready for release by the trigger.

In Figs. through 8 I have shown another modification of my basic idea wherein the cocking element is aseparate member supported independently of either firing pin or action tube finger but having operative engagement with both.

In this modification the cocking element is a multiarmed lever member 42 which is slidable on the shank of a post 43 and is urged forwardly thereon by a spring 44. Preferably, the spring 44 is a combined compression and torsion spring being formed with a leg 45 engaging a notch 46 in thehead of the post 43 and with a leg 47 engaged in a hole 48 in the body of the cocking lever member 42. The torsion action of the spring is such that, as viewed in Fig. 8, the tendency is to rotate the lever member in a clockwise direction. Rotation of the lever member is restrained by the guide stud 49 mounted in the breech block 4 and projecting rearwardly therefrom between the arms 50 and 51 on the lever member. The dotted line position in Fig. 8 is the normal position of the lever member with the arm 58 riding against the guide stud 49 and the arm 51 positioned over the end of the action tube finger 52. In either position of the lever member, another arm or flange 53 lies beneath the enlarged portion 54 of the firing pin body.

As the stud driver is advanced toward the work, the action tube finger 52' projects through the frame plate and breech block and, as discussed in the other modifications, it will engage the arm 51 and arrest the movement of the lever member. Since the arm or flange 53 lies beneath the enlarged portion 54 of the firing pin body, the firing pin will also be arrested while the stud driver is advanced to a position cocking the firing pin spring 55. Fig. 5 shows the elements just described in this cocked position.

Release of the firing pin is eifected by pulling rearwardly on the trigger 56 which engages arm 57 (Fig. 5) on the disconnector 58 and swings that member about its pivot stud 59 (Fig. 8) to bring the arm 60 into engagement with arm 50 of the lever member 42 and to rotate the lever member counter-clockwise about the post 43 into the position shown in Figs. 6 and 8. Referring particularly to Fig. 8, it should be obvious that rotation of the lever member from the dotted line position to that shown in full lines will slide the arm 51 off of the end of the action tube finger 52, allowing the firing pin spring to drive the firing pin forwardly. Although it should be obvious that the lever member might also have been disengaged from the firing pin, I have found that the simplest design may be achieved by allowing the lever member to return forward still in engagement with the firing pin. This may be done without sacrifice in the strength of the firing pin blow, since the spring 44 continuously acts to drive the lever member forwardly once it is released from constraint by the action tube finger.

Obviously, in each of the modifications so far described, it is necessary to provide some means of retracting the firing pin to a point clear of the front face of the breech block in order to permit opening the breech which requires relative swinging movement between breech block and frame plate. By the means illustrated in Figs. 7 and 8, I can accomplish such firing pin retraction and at the same time provide an auxiliary manually operable safety device.

As in the case of my prior application, I provide a slidable breech block latch 61 having attached thereto a pin 62. This pin is arranged for simultaneous engagement in a slot 63 in the frame plate and a slot 64 in the breech block 4, thus preventing the relative rotation of these members to a position opening the breech of the barrel. This latch may be pushed in a direction which is upward, as seen in Fig. 7, or to the left, as; seen in Fig. 8, to a degree suflicient to move the pin 62 beyond the extremity of the slot 63 and the opposed slot in the breech block 4, thus clearing both slots and permitting the relative swinging movement of breech block and frame plate required to expose the breech of the barrel. A tension spring 65 engaged between a pin 66 on the latch and a guide stud 67 in the breech block acts to hold the latch in its normal latching position, which is the position shown in dotted lines in Figs. 7 and 8. The normal position of the latch would, however, be that shown in full lines in Figs. 7 and 8 if it were not for the interposition of the plunger 68 mounted in the breech block for limited sliding movement and projecting into the path of the pin 62. This plunger is backed up by a spring 69 which is a stronger spring than the spring 65, thus normally urging the plunger 68 to its maximum extension and establishing the tip of the plunger as a stop for the latch in the normal dotted line position. Thus, it can be seen that the latch is movable in one direction to an extreme position not shown but beyond the dotted line position against the urging of the spring 65 to permit opening the breech of the barrel. The latch is also movable in the other direction from the normal dotted line position to that shown in full lines against the urging of the spring 69 to perform a safety function which will next be described. There are, therefore, three positions of the latch, in one of which the firing pin is retracted and the breech unlatched to permit breech opening, in one of which the safety is operative but the breech is locked closed, and one in which the breech is locked closed and the safety has been moved to an inoperative position.

As previously pointed out, the fact that the firing pin is urged to project through the faceof the breech block whenever it is not cocked makes it necessary to provide for firing pin retraction when the breech of the barrel is to be exposed. Similarly, this arrangement would tend to hold the firing pin against the primer of a loaded cartridge until the firing pin was cocked, which would present a serious hazard in case the stud driver should be dropped muzzle-down or given some other sharp jar producing an inertia force tending to further project the firing pin. In addition, it is always desirable to provide a stud driver with a manually operable safety which is so remote from the trigger as to require an operator to use one hand to operate the safety and another hand to operate the trigger. The operator is thus constrained to have both his hands in a safe position and the coordinated effort required minimizes the chances of accidental or careless firing. The breech block latch described above furnishes a convenient means of solving all of the problems referred to in this paragraph.

Referring particularly to Fig. 8, it will be seen that a portion of the breech block latch 61 is cut out to define nearly a semi-circle 70 which is, in this view, concentric with the firing pin body. This cutout 70 has its edge formed to define a conical-surface of least diameter adjacent the face of the breech block. As seen in section in Figs. 7 and 9, this cutout 70 defines a wedge. It Will also be noted that the forward corner 71 of the firing pin body is broken sufficiently to permit the conical surface 70 on the latch to enter beneath it and to have a wedgelike engagement for retracting the firing pin.

In the normal operation of this tool the breech block latch is pushed upwardly (Fig. 7) as far as it will go to position the pin 62 beyond the slots in the frame plate 2 and the breech block 4' to unlock the breech and simultaneously the wedge action of the cutout 70 retracts the firing pin. After extracting the fired cartridge and reloading, the breech may be closed and the breech block latch will come to rest in the position shown in Figs. 7, 8, and 9 in dotted lines, still holding the firing pin retracted. To permit firing, it is necessary to press the latch inward in opposition to the spring 69 and to hold it in the position shown in full lines in Figs. 7, 8, and 9, in which the coned cutout 70 is concentric with the firing pin and offers no impediment to full projection thereof.

In summary of the operation of the stud driver with my improved fire control, it may be noted that the breech may first be opened by release of the breech block latch and simultaneous retraction of the firing pin followed by relative swinging movement of breech block and frame plate. A loaded cartridge and stud may then be inserted into the barrel and the breech closed.

The barrel of the tool may then be centered over the place where a stud is to be driven with the shield 14 in engagement therewith and the remainder of the stud driver mechanism advanced toward the work until the muzzle end of the barrel approaches the work. During this manual advancement of the major parts of the stud driver, the action tube extension, action tube, and action tube finger remain stationary.

During the advancement of the stud driver toward the work the cocking element, like the action tube finger, remains stationary and functions of prevent firing pin advancement relative to the action tube finger. The firing pin will, therefore, maintain a stationary position as the stud driver advances toward the work, resulting in cocking the firing pin spring. With one hand the breech block latch may be pressed over into the position shown in full lines in Figs. 7 and 8 to clear the path for the firing pin and with the other hand the trigger may be pulled to operate the disconnector and release the firing pin from the position in which it is held by the action tube finger and the cocking element.

If, prior to actual firing, the operator should be called away or change his mind about driving a stud in a particular location, he may pick up the tool with assurance that the. firing pin will be lowered gradually to a safe position of rest against the breech block latch.

Although I have shown only three specific embodiments of my invention, it should be obvious that equivalent constructions may be used for various elements. For example, it is not necessary, although quite convenient, to utilize an action tube and action tube extension as the elements projecting in advance of the rest of the tool to cock the firing pin. Obviously, some other work surface engaging member could be utilized with entirely satisfactory results. It should therefore be noted that the claims appended hereto, rather than the extent of the specific disclosure above, establish the limits upon the scope of what I consider to be my invention.

I claim:

1. A fire control device for an explosively actuated stud driver having a barrel through which studs are to be driven, a frame plate mounted on the breech end of the barrel, a breech block secured in facial engagement with the frame plate to serve as a closure for the breech end of said barrel and a breech housing enclosing a space bounded on one side by said breech block; said fire control device comprising an action tube telescoped over said barrel, an abutment fixed with respect to the frame plate, a spring engaged between said abutment and the action tube urging the muzzle end of said action tube to project in advance of the muzzle of said barrel, a work surface engaging member on the muzzle end of said action tube, a finger on the breech end of the action tube extending parallel to said barrel in the direction of said breech block, openings in said frame plate and breech block aligned with said finger, said finger projecting through said breech block into said breech housing when the muzzle end of said action tube is stopped by engagement with a work surface while the stud driver is manually advanced toward said work surface to cause the muzzle of the barrel to approach said work surface, a firing pin reciprocably mounted in said breech housing, a firing pin spring engaged between said housing and the firing pin urging the firing pin to move toward said barrel, means to cock said firing pin comprising a cocking element releasably engageable between said finger and said firing pin to releasably hold said firing pin in a fixed position relative to the work surface against the urging of the firing pin spring when the stud driver is manually advanced toward said work surface to cause the muzzle of the barrel to approach said work surface, and manually operable disconnecting means mounted in said breech housing and operable to release said cocking element from holding. engagement between said finger and said firing pin.

2. A fire control device as described in claim I, said disconnecting means being so positioned Within said housing as to be engageable with said cocking element to release same only when said barrel has been advanced toward the work surface nearly into contact therewith, said firing pin being. thereby brought to a cocked position.

3. A fire control device as described in claim 2, including a manually operable trigger mounted on said breech housing in operable engagement with the disconnector, said disconnector comprising. a lever pivotally mounted in said housing whereby the end thereof engageable with said cocking element describes an arcuate path on actuation of s'aid trigger, which arcuate path intercepts and permits engagement with said cocking element only when said firing pin is in a substantially full cocked position 4. A fire control device as described in claim 3, said cocking element being a plunger slidably mounted in said firing pin and spring-urged to project outwardly therefrom into intersection with the said finger when the finger proiects into the breech housing.

5-. A fire control device as described in claim 3, said cocking element being. movably mounted in said housing by separate guide means supported on said breech block, said cocking element being engageable with both said firing pin and said finger to releasably hold said firing pin in a fixed position relative to a work surface as the stud driver barrel is manually advanced toward that work surface.

6. A'fire control device as described in claim 5, said cocking element mounting means comprising a post mounted in said breech plate substantially parallel to the line of reciprocation of said firing pin and to a line extending from said finger, said cocking element being.

mounted on said post for movement along the longitudinal axis of said post.

7. A fire control device as described in claim 6, said cocking element being both movable along the longitudinal' axis of said post and swingable about the axis thereof, said cockingv element having one arm engageable with said firing pin and another arm engageable with said finger, at least one of said arms being disengageable from the member to which it is engaged by swinging movement of said arm about the axis of said post.

8'. A fire control device as described in claim 7, wherein said cocking element mounted on said post comprises spring means mounted on said post and engageable with said cocking element to urge same to a position on said post adjacent to said breech plate.

9. A fire control device as described in claim 8, said spring means being a combined compression and torsion spring interconnected between said post and said cocking element to act both to urge said cocking element to the forward position adjacent thebreech plate and to oppose swinging movement of said element about the axis of said post to a position out of engagement with both said firing pin and said finger.

No references cited. 

